| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust purification device of an internal combustion engine capable of: preventing a urea water supply system which supplies an engine exhaust passage with urea water to purify NOx in exhaust from being damaged due to freezing of the urea water; preventing the urea water from solidifying in the urea water supply system; and curbing a delay in a start-up of the exhaust purification system.SOLUTION: An exhaust purification system 100 as an exhaust purification device of an internal combustion engine has, on an exhaust passage 12 of an engine 50: an SCR catalyst 1 which selectively reduces NOx in exhaust; an addition valve 2 which supplies urea water to an upstream side of the SCR catalyst 1; piping 13 which connects a urea water tank 8 and the addition valve 2; and a pump 7 which sends the urea water to the addition valve 2 through the piping 13. An ECU 11 recovers the residual urea water in a urea water supply system which is made up of an injector 2 and the piping 13 into the urea water tank 8 by inversely driving the pump 7 after stopping the engine 50. The ECU recovers the urea water in a manner that leaves a predetermined amount of the urea water in the urea water supply system. |
